JPS61247916A - Composite navigation system for ship - Google Patents

Abstract

PURPOSE:To make possible the exact detection of a ship's position by making such prescribed calculation as to eliminate drawbacks by taking advantage of an inertia navigation method and GPS receiver. CONSTITUTION:A speed error calculation unit 12 compares the speed information from a speed display device 6 of the inertia navigation device A and the speed information from a GPS speed display device 10 and calculates the error thereof. A position error calculation unit 13 compares the position information from a position display device 7 of the device A and the position information from a GPS position display device 11 and calculates the error thereof. A karman filter 14 is incorporated therein with the ship model expressing mathematically the movement of the ship and takes out only the change-component of the course controllable by the rudder out of the signals inputted thereto. The output from the filter 14 is impressed to the auxiliary circuits provided respectively to the output side from an accelerometer 1 and the output side of a platform correction and calculation unit 5 to correct the respective signals.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a combined ship navigation system that can accurately determine the position of a ship in crowded sea areas such as in ports and narrow waterways.

[Conventional technology]

Conventionally, inertial navigation, GP
There are methods using an S receiver, methods using Loran, Omega, NN58, etc.

[Problem that the invention seeks to solve]

However, inertial navigation has a problem in that compound errors increase over time due to factors such as inertial sensor errors, initial attitude errors, azimuth errors, calculation errors in the rotational speed of the earth and the moving speed of the ship. Additionally, the information available for civilian use using the GP8 receiver is less accurate than that for military use.
In addition, since the data is dispersed, there is a problem in that it is not possible to measure the ship's position with high precision, which is required in a port or in a sea area where narrow waterways pass.

In addition, other methods such as Loran, Omega, and NN5S all had poor accuracy and were hardly practical to use in lively areas.

For this reason, conventionally, when navigating in turbulent waters, it is necessary to deploy many people such as lookout personnel, radar monitoring personnel, and chart personnel. It was difficult to ensure safe navigation.

The present invention has been made in view of these problems in the prior art, and its purpose is to be able to accurately know the position of a ship, thereby preventing collisions with other ships, grounding accidents, etc. The aim is to realize a composite marine navigation system that allows ships to navigate safely with fewer personnel.

[Means for solving problems]

In order to solve the above problem, the present invention provides an error calculation unit that inputs information output from an inertial navigation device and information output from a GPS receiver, compares them, and calculates the error;
A position prediction calculation unit that inputs the error through a Kalman filter and performs predetermined calculations to predict the ship's position R; and a CRT that superimposes and displays the predicted position on an electronic chart.
The present invention provides a marine vessel composite navigation system including a display device.

[For production]

The position prediction calculation unit performs predetermined calculations that take advantage of the strengths of both the inertial navigation system and the GPS receiver and eliminate the shortcomings of each. displayed with precision,
This is done so that the ship's position can be accurately determined.

〔Example〕

Embodiments of the present invention will be explained in detail below using the drawings. Figure 1 is a block diagram showing an example of the system of the present invention, Figure 2 is a flow diagram of the system, and Figure 6 is a diagram of each sensor and device. It is an explanatory view showing the installation position.

In each of these figures, A is an inertial navigation system for ships, and B is a composite navigation system. The marine inertial navigation system A receives signals from an accelerometer 1 that detects the acceleration of the vessel, a platform servo 2 that controls the safety platform on which the accelerometer 1 is mounted, a gyro compass 3 that detects the direction, and the accelerometer 1. Then, the navigation calculation unit 4 calculates the ground speed and position, and the signal from this navigation calculation unit 4 is input, and the correction calculation is made based on the earth's rotation rate and movement rate.
It is comprised of a platform correction calculation unit 5, a speed indicator 6 and a position indicator 7 which display the output of the navigation calculation unit 4.

Composite navigation device B includes a GPS receiver 9 that inputs a signal from a GPS antenna 8, a QPS position indicator 11 and a GPS speed indicator 10 that display the output from this GPS receiver 9, a speed error calculation unit 12, and a position An error calculation unit 16, a Kalman filter 14 that processes each error output from each calculation unit 12 and 13, a position prediction calculation unit 15 that inputs the output from this Kalman filter 14 and performs a predetermined calculation to predict a position; C displaying the output of the prediction calculation unit 15 superimposed on the electronic chart;
It includes an RT display 16, an electronic chart storage device 17 that stores an electronic chart, a digital clock 18, a printer 19 that prints the output of the position prediction calculation unit 15, and a Doppler speed log display 22 that displays the Doppler speed log output. It is made up of. Note that the X-axis Doppler speed log 20 and the Y-axis Doppler speed log 21 are used as a backup device for speed information.

The speed error calculation unit 12 compares the speed information from the speed indicator 6 of the inertial navigation device A and the speed information from the GPS speed indicator 10, and calculates the error.
The position error calculation unit 16 compares the position information from the position indicator 7 of the inertial navigation device A and the position information from the GPS position indicator 11, and calculates the error.

Further, the Kalman filter 14 has a built-in ship model that mathematically represents the movement of the ship, and extracts only changes in the course that can be controlled by the rudder from the input signals. The output of this Kalman filter 14 is applied to correction circuits provided on the output sides of the accelerometer 1 and the platform correction calculation unit 5, respectively, to correct each signal.

The operation of the device configured in this manner will be described next. In the inertial navigation equipment A, the navigation calculation unit 4 uses the signal from the accelerometer 1 to calculate position information and speed information,
The results are displayed on the position indicator 7 and the speed indicator B, respectively. Furthermore, the GP8 receiver 9 similarly outputs position information and speed information, which are displayed on the position display 11 and speed display 10, respectively. Position error calculation unit 13
and speed error calculation unit 12 compares the signals from the position indicators 7, 11 and the speed indicators 6, 10, respectively, and calculates the position error and speed error, respectively.

The position error and velocity error from each of these calculation units 16 and 12 are processed by a Kalman filter 14, and further processed by a position prediction calculation unit 15 to take advantage of the strengths of inertial navigation and GPS receiver, and to eliminate the drawbacks of each. A predetermined calculation such as erasing is performed to predict the position and velocity. The position and speed signals from the position prediction calculation unit 15 are superimposed on the electronic chart output from the electronic chart storage device 17 and displayed on the CRT display 16.

Here, within an extremely short period of time (for example, several seconds), the position information from the navigation calculation unit 4 of the inertial navigation device is extremely accurate, and the position information from the GPS receiver 9 is data that is dispersed. The exact location is difficult to estimate. On the other hand, over a long period of time (for example, several hours), the navigation calculation unit 4
The positional information of the QPS receiver 9 is subject to divergence and the error increases, but since the data dispersion of the positional information of the QPS receiver 9 is always the same, the error remains almost constant regardless of the passage of time. In this device, the position prediction calculation unit 15 performs predetermined calculations to take advantage of the strengths of both the inertial navigation device and the GPS receiver and eliminate the drawbacks.
Compared to the positional information of the receiver 9 alone, the error is reduced to about % or less, and the positional accuracy is improved by about twice as much. Moreover, by preparing the electronic nautical charts of the entire world in the storage device 17, it is possible to
It can be used continuously for 24 hours.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to accurately know the position of a ship, and it is possible to prevent collisions with other ships and grounding even in crowded sea areas such as in ports and narrow waterways. This makes it possible to realize a combined ship navigation system that allows safe navigation with fewer personnel.

[Brief explanation of drawings]

FIG. 1 is a configuration block diagram showing an example of the system of the present invention,
FIG. 2 is a system flow diagram, and FIG. 3 is an explanatory diagram of the installation positions of each sensor and device. A... Inertial navigation device for ships, B... Composite navigation device,
4... Navigation calculation unit, 9... GPS receiver, 1
2... Speed error calculation unit, 13... Position error calculation unit, 14... Kalman filter, 15...
Position prediction calculation unit, 16...CR, T display, 17... Electronic chart storage device.

Claims (1)

[Claims] An inertial navigation device mounted on a ship and outputting position information and speed information of the ship, a GPS receiving device outputting position information and speed information of the ship, information output from the inertial navigation device and the GPS receiving device an error calculation unit that calculates the error by comparing the information output from the
a position prediction calculation unit that inputs the error from the error calculation unit via a Kalman filter and performs a predetermined calculation that takes advantage of the respective strengths of the inertial navigation and GPS receiver and eliminates the drawbacks to predict the position of the ship; , and a CRT display that superimposes and displays the predicted position from this position prediction calculation unit on an electronic nautical chart.